Added Double Linked list

C++/DoubleLinkedList/doublylinkedlists.cpp

@@ -0,0 +1,188 @@
+#include "stdio.h"
+#include "conio.h"
+#include "iostream"
+using namespace std;
+int insertdata(int x);
+void display();
+void deleteint(int x);
+void reversel();
+int searchint(int x);
+int compare_fn(int a,int b)
+{
+    if(a>b)
+        return 1;
+    else if(b>a)
+        return -1;
+}
+int compare_no=1;
+struct node
+{
+int data;
+node *prev;
+node *next;
+};
+node *top = NULL;
+int main()
+{
+    int ch,d,y;
+    char ans='y';
+    while(ans=='y')
+    {
+        cout<<"\n\t 1.Insert        2. Delete        3.Reverse    5.EXIT\nEnter Choice : ";
+        cin>>ch;
+        if(ch==1)
+        {
+            cout<<"Enter An Element To be inserted : ";
+            cin>>d;
+            d=insertdata(d);
+            display();
+        }
+        else if(ch==2)
+        {
+            cout<<"Enter Element To Be Deleted : ";
+            cin>>d;
+            deleteint(d);
+            display();
+        }
+        else if(ch==3)
+		{
+            reversel();
+		}
+		else if(ch==4)
+		{
+            display();
+		}
+        else
+            return 0;
+    }
+    return 0;
+}
+int searchint(int x)
+{
+int count=0;
+node *searchele=top;
+while( searchele!=NULL)
+{
+    if(compare_fn(x,searchele->data)==compare_no)
+    {
+        searchele=searchele->next;
+    count+=1;
+    }
+    else
+        break;
+}
+return count;
+}
+int insertdata(int x)
+{
+    if(top==NULL)
+    {
+        top=new node;
+        top->data=x;
+        top->next=NULL;
+        top->prev=NULL;
+    }
+    else if(compare_fn(top->data ,x)==compare_no)
+    {
+        node *n=new node;
+        n->data=x;
+        n->next=top;
+        n->prev=NULL;
+        top->prev=n;
+        top=n;
+    }
+    else
+    {
+    int c=searchint(x);
+    node *insertele=top;
+    for(int i=0;i<c-1;i++)
+        insertele=insertele->next;
+    node *n=new node;
+    n->data=x;
+    node *b=insertele->next;
+    node *N =insertele;
+    n->prev=insertele;
+    n->next=b;
+    insertele->next=n;
+    if(b!=NULL)
+        b->prev=n;
+    }
+}
+void display()
+{
+cout<<"Element In The Linked List Are : ";
+node *disp=top;
+while(disp!=NULL)
+{
+    cout<<" "<<disp->data;
+    if(disp->next==NULL)
+    {
+        break;
+    }
+    disp=disp->next;
+}
+}
+void deleteint(int x)
+{
+    node *del=top;
+    if(del->data == x)
+    {
+        if(del->next==NULL && del->prev==NULL)
+        {
+            top=NULL;
+            return;
+        }
+        del->next->prev=NULL;
+        top=del->next;
+    }
+    else
+    {
+        node *delsuc=del->next;
+        if(del==NULL)
+        {
+            cout<<"\nElement Not Found\n";
+            return;
+        }
+            if(delsuc==NULL)
+        {
+            cout<<"\nElement Not Found\n";
+            return;
+        }
+        while(delsuc->data != x)
+        {
+            del=del->next;
+            delsuc=delsuc->next;
+            if(del==NULL)
+        {
+            cout<<"\nElement Not Found\n";
+            return;
+        }
+            if(delsuc==NULL)
+        {
+            cout<<"\nElement Not Found\n";
+            return;
+        }
+        }
+        del->next=delsuc->next;
+        if(delsuc->next!=NULL)
+        delsuc->next->prev=del;
+    }
+}
+void reversel()
+{
+node *a=top;
+node *b,*c,*d;
+while(a!=NULL)
+{
+    d=a;
+    c=a->next;
+    b=a->prev;
+    a->prev=a->next;
+    a->next=b;
+    a=c;
+}
+top=d;
+cout<<"After Reversing the linked list";
+display();
+compare_no*=-1;
+}